FDA: Gardasil approved to prevent anal cancer

On Dec 22, 2010, the Food and drug Administration approved Gardasil, a vaccine made by Merck and Co Inc. for the prevention of anal cancer and associated precancerous lesions in people ages 9 to 26 years.

The FDA said about 90 percent of anal cancer is associated with human papillomavirus (HPV) types 6, 11, 16 and 18.

An estimated 5,300 people are expected to be diagnosed with anal cancer each year in theh U.S., the American Cancer Society was cited as saying .

The cancer is considered rare. According to the National Cancer institute, the lifetime risk is about 0.16 percent for men and women who are born today to develop anal cancer.

Overall, half men and about one third of women in the U.S. are expected to develop one cancer or another in their lifetime. One in seven women are expected to acquire breast cancer in their lifetime.

Gardasil has already been approved for the prevention of vulgar, cervical and vaginal cancer and associated precancerous lesions caused by HPV types 6, 11, 16, and 18 in females and for the prevention of genital warts caused by types 6 and 11 in both males and females.

Half of men and women are expected to get infected with HPV in their lifetime and in most cases, the virus can be cleared without medical intervention in one to two years of infection.

The FDA decision to allow Merck to market its Gardasil for the prevention of anal cancer was based on results of a trial of men who claimed they had sex with men, who are known to be at higher risk of anal cancer due to the exposure to HPV types 16 and 18.

The results showed at the end of the trial, Gardasil was effective in 78 percent of participants for the prevention of HPV 16 and 18 related anal intraepthelial neoplasia. The FDA assumed the same efficacy is applicable to females as well.

The FDA said it is important to get the vaccine at 9 to 26 because the vaccine cannot prevent the development of anal cancer after a person gets infected with HVP virus.

The health agency did not cite severe adverse effects associated with Gardasil, but said the most common reported adverse events include fainting and pain at the injection site.

The Centers for Disease Control and Prevention reports on its website that as of Sept 30, 2010, about 32 million doses of Gardasil were distributed in the U.S. and 17,160 reports of adverse events following Gardasil vaccination were filed to the Vaccine Adverse Event Reporting System or VAERS.

The CDC says 8 percent of the reported cases are considered serious adverse events including Guillain-Barré Syndrome (GBS) (the CDC did not say how many cases), blood clots and 56 U.S. reports of death among females who have received Gardasil.

The CDC denies that these deaths and serious adverse effects have anything to do with Gardasil vaccination. It says no evidence proves that the vaccine causes the severe adverse events.

The reports of adverse events associated with Gardasil vaccine have increased to 20,443 as of Nov 29, 2010. And a 10-year old boy reportedly died eight days after receiving Gardasil.